Troubleshooting 5-6yr old crack+speedball after static shock

[Halvy]

Hi all, I built my crack + speedball upgrade ~5-6 years ago. It's worked flawlessly over that time period. However recently the right channel has ceased playing any sound. There's no crackling or buzzing, just silence. The left channel seems ok. I was trying to think through what might have happened and I did remember accidentally static shocking it one day while cleaning up my desk (wool socks + carpet = bad combo I guess).

I broke out my multimeter and here's the results:

OA: 79.4v
OB: 79.7v
G: 0v
B+: 198.6v

Upon closer inspection the LED on D2 is not lighting up but it looks like all other LEDs are.

This is the only electronics project I've ever really done, so I'm not exactly sure how to troubleshoot from here. It seems weird to me that a random static electric shock would be enough to cause damage but I really can't think of anything else that might have triggered this.

I've attached a few photos and am happy to run some further checks. I've unfortunately lost my original crack assembly pdf and only have my crack upgrade pdf. I remember there being a longer voltage check in the original but just couldn't find my old document. Let me know if there are specific terminals that a further voltage check would be helpful to run.

Thank you in advance for the time and energy. I tried searching on the forum and clearly this is a very welcoming and helpful community.

~Andrew

 

[Paul Birkeland]

Can you list these voltages:

Small Board IA, IB, OA, OB.

Large Board IA, IB, OA, OB, B+.

You've given I would guess the voltages on the larger PC board, but that's not 100% certain. 

 

[Halvy]

Thanks for the quick reply. The OA and OB checks were from the smaller board and the B+ and G checks were from the larger board. Apologies, I forgot there were 2 separate tests for each board. I don't see IA and IB listed on the larger board but I went back and looked at the document I have and followed those steps.

Small board:
IA: 198.5v
IB: 198.6v
B-A/B: 0V
OA: 78.5v
OB: 79.1v

Large board:
OA: 117.9v
OB: 132.5v
B+: 198.1v
G: 0v

the board says v1.1 if that's helpful. The OB terminal did something weird on the larger board as I tested it. When I first tested it it read ~190v but as I left the positive red probe on, the voltage crept all the way down to 132.5v before stabilizing and reading a constant value.

 

[Paul Birkeland]

The voltages you posted are consistent with a working amplifier. The behavior you noted on OB on the big board would have me wanting to reflow the solder joints on that board.

 

[Halvy]

Just reflowed the joints on the big board. Unfortunately getting the same readings as before.

 

[Paul Birkeland]

I would continue by reflowing the rest of the joints in the amp other than where the two LEDs and the black wire land on the center post of the 9 pin socket.